Similar Datasets
Project description:Over evolutionary timescales, the logic and pattern of cell-type specific gene expression can remain constant, yet the molecular mechanisms underlying such regulation can drift between alternative forms. Here, we document a new, especially clear example of this principle in the regulation of the haploid-specific genes across a wide group of fungal species. For most species, transcription of these genes is repressed in the a/ a cell type by a heterodimer of two homeodomain proteins, Mata1 and Mata2. We show that in the species Lachancea kluveri, repression of one haploid-specific gene (GPA1) requires, in addition to Mata1 and Mata2, a third regulatory protein, Mcm1. Model building, based on x-ray crystal structures of the three proteins, rationalizes the requirement for all three proteins: no single pair of the proteins is optimally arranged and we show that no single pair can bring about repression. Although the three-part solution is used to regulate GPA1 in L. kluveri, the other haploid specific genes in this species are regulated by the more conventional two-protein mechanism. This case study exemplifies the idea that the energy of DNA binding can be “shared out” in different ways and can result is different DNA-binding solutions across different genes—while maintaining the same pattern of gene expression.
2023-02-22 | GSE221890 | GEO
Project description:Over evolutionary timescales, the logic and pattern of cell-type specific gene expression can remain constant, yet the molecular mechanisms underlying such regulation can drift between alternative forms. Here, we document a new, especially clear example of this principle in the regulation of the haploid-specific genes across a wide group of fungal species. For most species, transcription of these genes is repressed in the a/ a cell type by a heterodimer of two homeodomain proteins, Mata1 and Mata2. We show that in the species Lachancea kluveri, repression of one haploid-specific gene (GPA1) requires, in addition to Mata1 and Mata2, a third regulatory protein, Mcm1. Model building, based on x-ray crystal structures of the three proteins, rationalizes the requirement for all three proteins: no single pair of the proteins is optimally arranged and we show that no single pair can bring about repression. Although the three-part solution is used to regulate GPA1 in L. kluveri, the other haploid specific genes in this species are regulated by the more conventional two-protein mechanism. This case study exemplifies the idea that the energy of DNA binding can be “shared out” in different ways and can result is different DNA-binding solutions across different genes—while maintaining the same pattern of gene expression.
2023-02-22 | GSE221835 | GEO
Project description:BackgroundThe characterization of DNA replication origins in yeast has shed much light on the mechanisms of initiation of DNA replication. However, very little is known about the evolution of origins or the evolution of mechanisms through which origins are recognized by the initiation machinery. This lack of understanding is largely due to the vast evolutionary distances between model organisms in which origins have been examined.ResultsIn this study we have isolated and characterized autonomously replicating sequences (ARSs) in Lachancea kluyveri - a pre-whole genome duplication (WGD) budding yeast. Through a combination of experimental work and rigorous computational analysis, we show that L. kluyveri ARSs require a sequence that is similar but much longer than the ARS Consensus Sequence well defined in Saccharomyces cerevisiae. Moreover, compared with S. cerevisiae and K. lactis, the replication licensing machinery in L. kluyveri seems more tolerant to variations in the ARS sequence composition. It is able to initiate replication from almost all S. cerevisiae ARSs tested and most Kluyveromyces lactis ARSs. In contrast, only about half of the L. kluyveri ARSs function in S. cerevisiae and less than 10% function in K. lactis.ConclusionsOur findings demonstrate a replication initiation system with novel features and underscore the functional diversity within the budding yeasts. Furthermore, we have developed new approaches for analyzing biologically functional DNA sequences with ill-defined motifs.
| S-EPMC3306766 | biostudies-literature
Project description:Lachancea kluyveri, a weak Crabtree positive yeast, has been extensively studied for its unique URC pyrimidine catabolism pathway. It produces more biomass than Saccharomyces cerevisiae due to the underlying weak Crabtree effect and resorts to fermentation only in oxygen limiting conditions that renders it as a suitable industrial host. The yeast also produces ethyl acetate as a major overflow metabolite in aerobic conditions. Here, we report the first genome-scale metabolic model, iPN730, of L. kluyveri comprising of 1235 reactions, 1179 metabolites, and 730 genes distributed in 8 compartments. The in silico viability in different media conditions and the growth characteristics in various carbon sources show good agreement with experimental data. Dynamic flux balance analysis describes the growth dynamics, substrate utilization and product formation kinetics in various oxygen-limited conditions. We have also demonstrated the effect of switching carbon sources on the production of ethyl acetate under varying oxygen uptake rates. A phenotypic phase plane analysis described the energetic cost penalty of ethyl acetate and ethanol production on the specific growth rate of L. kluyveri. We generated the context specific models of L. kluyveri growing on uracil or ammonium salts as the sole nitrogen source. Differential flux calculated using flux variability analysis helped us in highlighting pathways like purine, histidine, riboflavin and pyrimidine metabolism associated with uracil degradation. The genome-scale metabolic construction of L. kluyveri will provide a better understanding of metabolism behind ethyl acetate production as well as uracil catabolism (pyrimidine degradation) pathway. iPN730 is an addition to genome-scale metabolic models of non-conventional yeasts that will facilitate system-wide omics analysis to understand fungal metabolic diversity.
| S-EPMC7530994 | biostudies-literature
Project description:Pyrimidines are important nucleic acid precursors which are constantly synthesized, degraded, and rebuilt in the cell. Four degradation pathways, two of which are found in eukaryotes, have been described. One of them, the URC pathway, has been initially discovered in our laboratory in the yeast Lachancea kluyveri. Here, we present the global changes in gene expression in L. kluyveri in response to different nitrogen sources, including uracil, uridine, dihydrouracil, and ammonia. The expression pattern of the known URC genes, URC1-6, helped to identify nine putative novel URC genes with a similar expression pattern. The microarray analysis provided evidence that both the URC and PYD genes are under nitrogen catabolite repression in L. kluyveri and are induced by uracil or dihydrouracil, respectively. We determined the function of URC8, which was found to catalyze the reduction of malonate semialdehyde to 3-hydroxypropionate, the final degradation product of the pathway. The other eight genes studied were all putative permeases. Our analysis of double deletion strains showed that the L. kluyveri Fui1p protein transported uridine, just like its homolog in Saccharomyces cerevisiae, but we demonstrated that is was not the only uridine transporter in L. kluyveri. We also showed that the L. kluyveri homologs of DUR3 and FUR4 do not have the same function that they have in S. cerevisiae, where they transport urea and uracil, respectively. In L. kluyveri, both of these deletion strains grew normally on uracil and urea.
| S-EPMC3910958 | biostudies-literature
Project description:We generated a genome-wide replication profile in the genome of Lachancea kluyveri and assessed the relationship between replication and base composition. This species diverged from Saccharomyces cerevisiae before the ancestral whole genome duplication. The genome comprises eight chromosomes among which a chromosomal arm of 1 Mb has a G + C-content much higher than the rest of the genome. We identified 252 active replication origins in L. kluyveri and found considerable divergence in origin location with S. cerevisiae and with Lachancea waltii. Although some global features of S. cerevisiae replication are conserved: Centromeres replicate early, whereas telomeres replicate late, we found that replication origins both in L. kluyveri and L. waltii do not behave as evolutionary fragile sites. In L. kluyveri, replication timing along chromosomes alternates between regions of early and late activating origins, except for the 1 Mb GC-rich chromosomal arm. This chromosomal arm contains an origin consensus motif different from other chromosomes and is replicated early during S-phase. We showed that precocious replication results from the specific absence of late firing origins in this chromosomal arm. In addition, we found a correlation between GC-content and distance from replication origins as well as a lack of replication-associated compositional skew between leading and lagging strands specifically in this GC-rich chromosomal arm. These findings suggest that the unusual base composition in the genome of L. kluyveri could be linked to replication.
| S-EPMC3590768 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2024-03-16 | GSE237708 | GEO
Project description:The Crabtree positive yeasts, such as Saccharomyces cerevisiae, prefer fermentation to respiration, even under fully aerobic conditions. The selective pressures that drove the evolution of this trait remain controversial because of the low ATP yield of fermentation compared to respiration. Here we propagate experimental populations of the weak-Crabtree yeast Lachancea kluyveri, in competitive co-culture with bacteria. We find that L. kluyveri adapts by producing quantities of ethanol lethal to bacteria and evolves several of the defining characteristics of Crabtree positive yeasts. We use precise quantitative analysis to show that the rate advantage of fermentation over aerobic respiration is insufficient to provide an overall growth advantage. Thus, the rapid consumption of glucose and the utilization of ethanol are essential for the success of the aerobic fermentation strategy. These results corroborate that selection derived from competition with bacteria could have provided the impetus for the evolution of the Crabtree positive trait.
| S-EPMC5345805 | biostudies-literature
Project description:S-phase time-course of Lachancea kluyveri cells
| PRJNA159189 | ENA
Project description:Petite-negative budding yeast (known as Lachancea kluyveri or Saccharomyces kluyveri) sequenced for comparative genomics studies
| PRJNA9594 | ENA